Expert: Alistair Brady, Commercial Air Diver
Where do you live?
What is your day job, what type of commercial diver are you?
Commercial Air Diver
How long have you been scuba diving?
4 years as a commercial diver, and I started scuba diving in 2001.
What made you decide to become a commercial diver?
I’m a passionate scuba diver, and decided I would like to get paid to do a job I love.
Did you have to have any other qualifications before starting class e.g. Open Water Cert?
How much did the initial training cost?
Where did you train at, and what did the training cover?
I trained in a 9 week course at The Underwater Centre in Fort William, Scotland:
- 1 week First Aid (classroom/theory+practical)
- 4 weeks Surface Supplied Diving using Kirby Morgan Surface Demand Helmets (diving practicals using power tools, lift bags & air lifts)
- 3 weeks Scuba (using Interspiro AGA Mask & Exo26 Full Face Masks)
- 1 week Top-up (Wet Bell with hot water suits)
Are there specialties commercial diving like in recreational diving?
There are specialties like saturation diving, wet welding, burning & cutting, inspection, construction & salvage. I specialize in inspection, welding and construction experience. I’m also a diver medic (each offshore team requires 1 diver medic).
What specialized equipment do you wear?
Full Surface Demand Diving spread including Kirby Morgan Dive Helmets, wetsuit, Bailout bottle (scuba emergency air supply) diving booties & Jetfins. Umbilical including Main Air, Depth gauge, Radio comms system & Live Video CCTV.
How does a commercial diving helmet differ from the many recreational full-face masks with communication?
Kirby Morgan Dive Helmets (KM17, 37 & KMB18, 28) include earphones and microphone for communication with dive supervisor. A non-return valve is located on the side of the helmet to switch to a back-up air supply (scuba bottle) in case of emergency. A free flow valve is also used to flush the helmet with extra air to prevent high carbon dioxide levels.
How deep are you certified to go and what is the deepest you have been?
160ft/50metres. I have dived to this depth a few times.
What is the strangest thing you have seen on a dive?
I have seen a whale shark circling our diving zodiac and then swimming by our divers on the same day.
Triggerfish sometimes like to eat the marine growth you have to remove from anchor chains or from oil tankers – they’re so close to you, sometimes they mistake your fingers for food!
How do you control your buoyancy, as you do not use BCD like devices?
It’s mainly through our breathing and we also normally use a strong small permanent magnet tied to our harness, to stick onto the work location.
Do you carry tools on you or do you have a tool bag/chest that is lowered with you?
Yes we use tool bags that are attached to us with all sorts of tools inside, but the heavy stuff like a hydraulic wrench would need to be lowered down to us. So a bit of both!
Has any critter ever tried to steal your tools?
No! Our tools are too big and heavy!
Have you ever found anything you were not expecting (like a wreck or fossil)?
How much time do you spend in the water each day, are you limited to a certain amount?
Depends upon depth. As the air supply is unlimited, shallow dives can last for hours. We do in-water decompression stops, and sometimes surface decompression in a decompression chamber.
Have you spent time living in a diving chamber (Saturation Diving), what is it like?
You have to undergo special training to become a saturation diver and live in a dive chamber for weeks at a time. However, I have used a chamber for decompression treatments and for assisting a casualty inside (diver medic). It’s often referred to as a dry dive, and that’s the best way to describe it. Air is blown into the chamber to mimic the same pressure you would feel underwater. Your voice becomes high pitched at deep depths (like Donald duck) and you can be susceptible to the effects of nitrogen narcosis.
What air mixtures do you breathe and what determines which mixture?
I use the air mixture for diving (21% oxygen) as it’s usable for up to the depth of our working range. Diving deeper than 160 feet/50 metres requires lower oxygen percentage mixtures. A dive at 100metres for example could use a mixture of 14% oxygen and 86% helium.
Walk us through a typical day.
Wake up at 5.30am, breakfast & shower, 7am toolbox talk for the day, get in the dive boat, each diver takes turns to dive, with the next diver fully dressed as a standby diver to rescue the working diver in the case of an emergency. Stop for a lunch hour and resume diving after. Each diver is usually limited to one dive per day. Normally off shift by 6pm. We stay onboard the vessel we are working from (oil rig/FPSO/platform/barge)
Do you dive for pleasure? When you are not working where is your favorite place to dive?
Yes! Out of all the places I have dived, The Maldives or Great Barrier Reef have to be the best locations for marine life.
Where are you planning on recreationally diving next and where?
After seeing a whale shark offshore my next ambition is to scuba dive with them, so I plan to go to Cozumel (near Cancun) in July.
If someone were interested in becoming a commercial diver what tips would you give him or her?
- Be prepared to dive in strong currents and bad visibility.
- Consider the financial side as the course as it is very expensive and there is no guarantee of work once qualified.
- Be prepared to take a lower-paid job at first to build your offshore experience.
- You have to be ready to spend a lot of time away from family and friends.
- To make your life easier offshore, make sure you know all type of rope knots and splicing, this little bit of knowledge really comes in handy!
- Familiarize yourself with crane signals.